Process of making anthraquinone.



' "on'rirn sr arns 51a Drawing.

FRITZ SINGER, 0F OFFENBACH-ON-THE MAIN, GERMANY, ASSIGNOR TO CORPORATION OF CHEMISCHE FAJBRIK GRIESHEIM-ELEKTRON, 0F FRANKFORT-ON-THE-MAIN,

GERMANY.

9Tb aZZ whom "it may concern:

Be it known that I, Fnrrz 7Eirzenn, citizen of the German Empire, and resident of Of-- fenhach-on-the-ldain, in the Grand Duchy of Hesse, Germany, have invented new and useful Improvements in Processes of Makmg Anthraquinone, of which the following Serial hlr. 810959 filed January 8, 1914, from Fritz is a specification.

In the-application for patent Singer and Ernst Milarch, assignors, there 1s described a process of making anthraquinone, consistmg H1 first treat1nganthracene with nitric acid at a temperature-under 60 C. in presence of an indifferent liquid and in then transforming the intermediate product thus obtained, which vis a mixture of unstable Ineso-nitro derivatives of anth'racene, into anthraquinone in presence of nitric. acid at higher temperatures than C. Now I have found, that for the {second phase of the reaction in'steadof nitric acid also other oxidizing agents among others in the first line other compoundsv of nitrogen, containing oxygen, and chlorin can be employed. 1 have further found, that phases of the process acts very advantageously upon the reaction,realiz-ing a plain progress of the reaction and an important augmentation of the yield of anthraquinone.

In order to illustrate the new process more fully, the following examples are given, parts being by Weight.

Example I: 117 parts of anthracene of 85% strength are suspended in 300 parts of nitrobenzene. At While stirring a solution 0f-3 parts of mercury in 460 parts of nitric acid of 31% strength is poured in 3 hours. Before all the nitric acid is added the mixture is completely dissolved.- The Specification of Letters Patent. I

dried. the addition of salts of; mercuryfor'both PROCESS OF MAKING ANTHRAQUINONE.

Patented Dec. 1, 1914".

Application filed May 25, 19M. Serial No. 840,753.

' 120, then at about 110 for nearly 10 minutes chlorin is introduced in the mixture forremoving organic compounds of mercury, formed in a little quantity. After cooling down the separated crystals of an'thraquinone are filtered, Washed with nitrobenzene and ben'zin and dried.

Example II: 117 parts of anthracene of strength are suspended in 300 parts of nitrobenzene. In 3 hou'rs'at 30 asolution of 15 parts of mercury in 460 parts of nitric acidof,3-1% strength is poured, and thefmixf i ture is stirred at 35 for 3 hours andfiltered,

if necessary. Then the "nitric-acid is ,sepa,-'

rated, After addition of-a.--solution of a mercury salt a strong' stream of-chlorinisintroduced 'while stirring-in ithe filtered nitrobenzene solution, and the mixture is eated at for nearly 20 minutes. The;

temperature 'is' rising while introducing chlorin continuously at -1209, the intro duction of chlorin and heating is continued for a time; After cooling down the separated crystals of anthraquinone are' filte'red; Washed with nitrobenzene and'benzin and In an analogous manner insteactof chlorin ture of both or othercomp ounds-easlily developing oxygen, such as manganese neroxid can be used.

I ,Now What I claim and desire to secure oy the dioxid or 'trioxid of nitrogenor a mix; I

q'uinone. by means of an oxidizing, agent after addition of a mercury salt at vhigher temperaturestnan 1'30"- I That I claim the foregolngas my invem ti0n,-,'Ihave signed my name in presence of f I,

two Witnesses, this sixth day of May 1914:.

' FRKTZSINGER.

Witnesses: v

Ps'rnn LAUTONSCHLZLGEB, FRITZ Dnson. 

